Electric dust collector

ABSTRACT

The electric dust collector has an oblong holding unit provided on the air channel of an air conditioner or the like; a high-voltage applying device provided at an end of the holding unit; a front-open contact protector of substantially inverted U-shape that contains a high-voltage power feeding terminal connected to the high-voltage applying device; a filter unit attached to the holding unit; and a slide projection provided on the filter unit. The slide projection has a high-voltage power receiving terminal removably fitted into the contact protector, allowing the filter unit to be removably attached to the holding unit. The high-voltage power feeding terminal covered with the contact protector is free from dust collection. The structure can prevent contact failure or electrical leak.

THIS APPLICATION IS A U.S. NATIONAL PHASE APPLICATION OF PCTINTERNATIONAL APPLICATION PCT/JP2004/009768, filed Jul. 2, 2004.

FIELD OF THE INVENTION

The present invention relates to an electric dust collector arranged inan air channel of an air conditioner to remove dust in air.

BACKGROUND OF THE INVENTION

Electric air purifiers arranged in air channels of conditioners areknown.

A conventional electric air purifier disclosed in Japanese PatentLaid-Open Publication No. 2003-106552 will be described with referenceto FIGS. 53 to 55. The air purifier includes holding frame 101,high-voltage power supply 102 provided at an end of holding frame 101,high-voltage terminal 103 and ground terminal 104 provided fromhigh-voltage power supply 102, and removable filter body 106 havingcontact point 105 between high-voltage terminal 103 and ground terminal104. Coil spring 107 or flat spring 108 is provided at least one ofhigh-voltage terminal 103 and ground terminal 104. High-voltage powersupply 102 is provided on holding frame 101 in a manner that eachelastic tip of terminals 103 and 104 projects from partition wall 109provided between high-voltage power supply 102 and a part through whichfilter body 106 is inserted.

Holding wall 110 provided at an end of holding frame 101 on the oppositeside of high-voltage power supply 102 to hold filter body 106 fittedinto holding frame 101. Filter body 106 is fixed between partition wall109 and holding wall 110 in a manner that projection 111 provided on theside surface on the opposite side of contact point 105 has engagementwith pit 112 provided on holding wall 110 of holding frame 101.

In the conventional air purifier, high-voltage terminal 103 connected tohigh-voltage power supply 102 easily collects dust, and the air purifieralso has a part exposed from the structure.

Filter body 106 is, as described above, fixed between partition wall 109and holding wall 110. When attached to or removed from the place, filterbody 106 tends to have torsion due to the oblong shape, and thereforethe installation work has often involved a difficulty.

Here will be described another electric dust collector having asynthetic resin-made holding frame, which is disclosed in JapanesePatent Unexamined Publication No. 2003-10731, with reference to FIGS. 56to 58. Needle-shaped discharge electrode 1103 is provided on the side ofwater inlet 1102 of resin-made holding frame 1101, and thenair-permeable ground electrode 1104 is provided so as to face dischargeelectrode 1103, furthermore, filter 1105 is located on the leeward sideof ground electrode 1104. Filter unit 1106 is thus formed. When filterunit 1106 is mounted on the dust collector, high-voltage applyingsection 1107 applies negative high voltage to discharge electrode 1103,and ground electrode 1104 provides ground connection. Such formedhigh-voltage applying device 1108 is provided on the air channel in anair conditioner and the like.

In the conventional dust-collecting unit, holding frame 1101 is made ofcommonly used synthetic resin, which easily collects dust due to chargedstatic electricity.

As another conventional electric dust-collecting unit, Japanese PatentLaid-Open Publication No. 2003-103196 discloses another electric dustcollector. The dust collector includes, in addition to the device thatapplies high voltage to a dust collecting section, a sound-wavegenerator that enhances dust collection efficiency. The dust collectorwill be described with reference to FIG. 59. Dust-collecting unit 2101contains housing 2102, discharge electrode 2103, counter-electrode 2104,and dust-collecting filter 2105. In addition, controller 2107 and switch2108 are provided so that direct current power supply 2106 providedoutside dust-collecting unit 2101 applies voltage to discharge electrode2103 and counter-electrode 2104. Furthermore, the dust collector hassound-wave generator 2110 on side section 2109 of housing 2102, andsound-wave controller 2111 for controlling sound-wave generator 2110.With the structure above, sound wave is applied to a corona dischargearea so as to enhance dust collection efficiency. Air flows in direction2201.

In the conventional electric dust collector, direct current power supply2106 for applying direct current to dust-collecting unit 2101,controller 2107, and switch 2108 are provided outside the dustcollector. Sound-wave generator 2110 is provided on side section 2109 ofhousing 2102 of the dust-collecting unit and is controlled by sound-wavecontroller 2111. That is, direct current power supply 2106, controller2107, switch 2108, sound-wave generator 2110, and sound-wave controller2111 can suffer mutual noise interference. The installation of thesecomponents away from dust-collecting unit housing 2102 not onlyincreases the wiring in length for connecting these components, but alsocomplicates measures against dust collection on each component.

As still another electric dust collection unit, Japanese Patent No.2856580 discloses an air purifier. Changing the shape of an elasticportion provided on a filter opens or closes a power circuit for ahigh-voltage power supply unit. The air purifier will be described withreference to FIGS. 60 and 61. The air purifier includes body 3102 havingremovable front panel 3101, removable pre-filter 3103 provided on body3102, high-voltage ionizier 3104 for removing dust in the air passingthrough pre-filter 3103, elastic portion 3105 provided on pre-filter3103, and detecting switch 3106 for detecting altered elastic portion3105. Elastic portion 3105 provided at pre-filter 3103 bends by beingpushed by front panel 3101 when pre-filter 3103 is mounted on body 3102.Detecting switch 3106 detects the deformation of elastic portion 3105.Detecting switch 3106 does not detect the deformation, a power supply tohigh-voltage ionizer 3104 is turned off.

In this conventional air purifier, elastic portion 3105 provided onpre-filter 3103 bends toward detecting switch 3106 by being pushed byfront panel 3101 when front panel 3101 is fixed to the body. If frontpanel 3101, pre-filter 3103, and detecting switch 3106 have positionalvariations, detecting switch 3106 cannot be activated accurately.

Besides, exposed detecting switch 3106 easily collects dust, which cancause faulty connections.

As yet another electric dust-collecting unit, Japanese Patent Laid-OpenPublication No. 2003-106552 discloses an electric air purifier for anair conditioner. The electric air purifier will be described withreference to FIG. 62. The air purifier includes holding frame 4101,high-voltage power supply 4102 provided at an end of holding frame 4101,high-voltage terminal 4103 and ground terminal 4104 provided fromhigh-voltage power supply 4102, contact point 4105 of high-voltageterminal 4103 and ground terminal 4104, and filter body 4106 removablyprovided to holding frame 4101.

In this conventional electric air purifier, high-voltage power supply4102 is provided on holding frame 4101, which is seen on the left sidein the drawing, and filter body 4106 is fixed on the right side ofhigh-voltage power supply 4102. Due to positional constraint in mountingon an air conditioner, high-voltage power supply 4102 cannot be providedon the right side of holding frame 4101.

High-voltage terminal 4103 and ground terminal 4104 are provided on onlyone side of the right and left sides of filter body 4106 to be mountedon holding frame 4101. Therefore, when filter body 4106 is removed fromholding frame 4101, filter body 4106 tends to have torsion, due toresistance of high-voltage terminal 4103 and ground terminal 4104, sothat the removing work has often involved a difficulty.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, an electric dustcollector includes an holding unit having an oblong shape provided in anair channel of an air conditioner, a high-voltage applying deviceprovided at an end of the holding unit, a contact protector opening tofront and having a cave shape facing substantially downward, a filterunit attached to the holding unit, and a slide projection provided atthe filter unit. The contact protector accommodates a high-voltage powerfeeding terminal connected to the high-voltage applying device. Theslide protection includes a high-voltage power receiving terminalremovably fitted into the contact protector so that the filter unit isremovably mounted on the holding unit.

This structure allows the high-voltage power feeding terminal to becovered with the contact protector, thus being prevented from havingdust attached thereto. The structure not only prevents contact failureor electrical leak that is possibly caused by dust, but also protectshands or fingers from accidentally touching the high-voltage powerfeeding terminal, thereby increasing safety. The electric dust collectorcan provide a simple structure less expensive than the structure inwhich application of high voltage is controlled by a limit switch.

According to another aspect of the invention, the electric dustcollector may include a guide rib provided on one of the holding unitand the high-voltage applying device so as to be parallel to a directionin which the filter unit is pulled out. A groove for accepting the guiderib is provided in the filter unit. The groove reaches substantially acenter of the filter unit. This structure allows the filter unit to besmoothly removed without torsion, preventing the filter from beingremoved with torsion.

According to still another aspect of the invention, the electric dustcollector may include a latching unit provided at an end of the filterunit opposite to an end at which the high-voltage power receivingterminal is provided. The filter unit is temporarily retained when thefilter unit is pulled out.

In the structure above, the end having the high-voltage power receivingterminal of the filter unit attaches to the holding unit tighter thanthe other end of the filter unit. The latching unit causes the “looser”end to be temporarily held until the “tighter” end is removed first. Thestructure allows the filter unit to be smoothly removed without torsion.

According to yet another aspect of the invention, the electric dustcollector may include a handle provided on the filter unit while biasedto the high-voltage power receiving terminal. A pulling-out force causedby the handle is applied strongly to a portion of the filter unit to thehigh-voltage power receiving terminal. The portion of the filter unit isattached to the holding unit tighter than the opposite side, whereby thetighter end can be pulled out at almost simultaneously to the otherside, encouraging a smooth pull-out of the filter unit.

According to another aspect of the invention, an electric dust collectorincludes an oblong holding unit mounted in an air channel of an airconditioner, a high-voltage applying device provided at an end of theholding unit, and a filter unit removably provided on the holding unit.The filter unit includes an air-intake grill having a shape having acenter projecting to front. The air-intake grill has a first dischargeneedle electrically connected to the high-voltage applying device. Thefilter unit further includes an air-permeable ground electrode providedon a leeward side of the first discharge needle, and an air-permeabledust-collecting filter provided on a leeward side of the first dischargeneedle. The air-intake grill includes a non-conductive rib made ofnon-conductive resin, and a conductive rib that is provided in a latticearrangement and is electrically connected to the ground electrode.

This structure can prevent an electrical charge buildup on theair-intake grill, thereby protecting the air-intake grill from dust.This provides not only a hard-to-collect-dust, i.e., easy-to-cleanair-intake grill, but also avoids shock hazards.

According to still another aspect of the invention, the first dischargeneedle has a tip surrounded by the conductive rib on a projection plane.

This structure causes the discharge needle to produce a corona dischargenot only at the ground electrode but also at the conductive rib of theair-intake grill. The structure extensively increases the discharge areaof negative ion, enhancing negative ionization of dust. This improvesfiltering efficiency of the dust collector, and prevents the air-intakegrill from collecting dust to an area.

According to still another aspect of the invention, the shortestdistance between the tip of the first discharge needle and the groundelectrode is substantially identical to the shortest distance betweenthe tip of the first discharge needle and the conductive rib of theair-intake grill.

This structure above allows each amount of discharge from the dischargeneedle to the ground electrode and to the conductive rib to be balanced,thereby providing stable filtering efficiency. This structure canprotect components provided on the side of the ground from unevenlycollected dirt due to imbalance of discharge and from deteriorationcaused by dirt.

According to still another aspect of the invention, the electric dustcollector may include a pawl provided at an end of the conductive rib ofthe air-intake grill, and an engaging section provided at the air-intakegrill and having a caving shape. The engaging section is engaged withthe pawl to fix the conductive rib.

This structure prevents arc discharge at the discharge needle and thetip of the conductive rib, enhancing safety. This structure providesreliable positioning of the conductive rib, simplifying an assemblingwork.

According to still another aspect of the invention, the ground electrodemay have a frame made of metal at a perimeter thereof. The electric dustcollector may further includes a connecting unit for connecting theframe of the ground electrode with the conductive rib of the air-intakegrill at a plurality of positions. The connecting unit holds thenon-conductive rib of the air-intake grill.

This structure can eliminate connecting parts, such as a screw, when theconductive rib is connected to the ground electrode for groundconnection, simplifying an assembling work. The assembling workcompletes a rigid filter unit as a combination of the ground electrodehaving a frame structure and the air-intake grill, with thenon-conductive rib is sandwiched therein. Such structured filter unithas enough strength so as to be tightly attached to the holding unit,preventing vibration noise caused by resonance in operation.

According to still another aspect of the invention, the electric dustcollector may further include a flat sub-electrode plate provided on theground electrode at a shortest distance from the first discharge needle.

This structure can protects a lath net forming the ground electrode fromcollecting dust caused by partial corona discharge to the edge of thelath net, preventing deterioration. Further, the structure can improvefiltering efficiency by increasing the area of corona discharge to theground electrode.

According to another aspect of the invention, the ground electrode mayhave a frame. The electric dust collector may further include adust-collecting filter accommodated in the frame of the groundelectrode, a burr produced on an outer side of the frame, and a filterunit frame for surrounding the filter unit through a clearance of theframe of the ground electrode. A frame wall-height of the filter unitframe measured from the ground electrode as a reference plane is largerthan a frame-height of the ground electrode. A thickness of thedust-collecting filter is larger than the frame-height of the groundelectrode.

This structure eliminates need for removing the burr by deflashing,thereby reducing manufacturing steps; accordingly, manufacturing cost.

According to still another aspect of the invention, the electric dustcollector may further include an inflexible dust-collecting filterhaving an opening and accommodated in the ground electrode. The filterunit may include a lattice-shaped filter frame for holding a side of theopening of the dust-collecting filter, and a small projection providedon the lattice of the filter frame and projecting toward thedust-collecting filter.

This structure provides a small space between the dust-collecting filterand the filter frame. The small space allows air flow to be evenlyprovided on the entire filter, improving filtering efficiency.

According to yet another aspect of the invention, the electric dustcollector may further include plural second discharge needles, and aneedle-shaped electrode unit for connecting the second discharge needlesto each other. The air-intake grill has a front side having an oblonggroove formed therein. The needle-shapes electrode unit has a shapeaccommodated in the oblong groove. The electric dust collector mayfurther include a bend strip having an L-shape fitted in a slideprojection provided on an edge of the filter unit. The bend strip servesas a high-voltage power receiving terminal of the needle-shapedelectrode unit. The collector may further include a needle-electrodecover for covering the needle-shaped electrode unit fitted in thegroove, and a pressing rib provided at the needle-electrode cover. Theneedle-shaped electrode unit has a dent portion formed therein. Thepressing rib contacts the dent portion of the needle-shaped electrodeunit as to fix the needle-electrode cover.

In this structure, the discharge needle can be accurately fixed to apredetermined position on the filter unit through simple installationwork without a screw or the like. This can prevent poor filteringefficiency caused by inaccurate installation work.

According to another aspect of the invention, an electrical device hasan electric dust collector including a filter unit and a holding unitarranged to have the filter unit attached to the holding unit. Theelectrical device may include an electrical box having a chamberprovided at an end of the holding unit, the electrical box having achamber having a top opening, a high-voltage power supply boardaccommodated in the electrical box, an ultrasonic wave oscillatoraccommodated in the chamber of the electrical box, and a lid forcovering the opening top of the chamber.

The arrangement that the high-voltage power supply board and theultrasonic wave oscillator are included in the electrical box canshorten wiring lengths, enhancing efficiency in workability andtransportation. Besides, the structure not only contributes to adownsized electric dust collector, but also protecting the ultrasonicwave oscillator and other components from collecting dust that can causedeterioration of ultrasonic wave radiation.

According to still another aspect of the invention, the electricaldevice may further include a bracket holder provided on a top surface ofthe lid, and a high-voltage power feeding bracket having one end andother end. The one end has a high-voltage power feeding terminal held bythe bracket holder. The other end has a high-voltage power connectorcontacting the high-voltage power supply board. The high-voltage powerfeeding bracket is fixed to the electrical box and contacts the lid ofthe chamber. The high-voltage power connector is pressed to contact thehigh-voltage power supply board.

This structure can fix the lid and the high-voltage power feedingbracket simultaneously, thereby increasing workability and decreasingparts count.

According to another aspect of the invention, he high-voltage powerfeeding bracket may be made of conductive metal plate, the end and theother end of the high-voltage power feeding bracket have elasticity, anda portion of the high-voltage power feeding bracket held by the bracketholder has rigidity.

The structure allows the high-voltage power connector and thehigh-voltage power feeding terminal to be formed without pluralcomponents, whereby a cost-reduced product is obtained. Besides, thefolded metallic plate can offer simple-structured secure fixing, withcontact points properly positioned.

According to still another aspect of the invention, the chamber may havean opening to supply an ultrasonic wave generated by the ultrasonic waveoscillator to the filter unit. The chamber and the lid provides atubular projection surrounding the ultrasonic wave oscillator andprojecting towards the opening.

The structure allows the ultrasonic wave from the ultrasonic waveoscillator to be guided by the tubular projection to the opening in thechamber, whereby the ultrasonic wave can be properly directed. At thesame time, dividing the tubular projection in two and disposing eachhalf on the chamber side and the lid side allows the ultrasonic waveoscillator to be vertically sandwiched between the halves. That is, thestructure can securely retain the ultrasonic wave oscillator even in thesmall chamber.

According to another aspect of the invention, the electrical device mayfurther include a lead wire provided from the high-voltage power supplyboard and a connecting terminal provided at the electrical box andconnected to the lead wire. The electrical box may have a small chamberprovided in the electrical box. The small chamber surrounds theconnecting terminal to protect the connecting terminal from dust.

This structure not only eliminates the need for additionally providinginsulation for protecting the connector, but also protecting the contactpoints from collecting dust, thereby enhancing safety.

According to another aspect of the invention, an electrical device hasan electric dust collector including a filter unit and a holding unit towhich the filter unit is mounted. The electrical device includes anelectrical box provided at an end of the holding unit, a high-voltagepower supply board accommodated in the electrical box, and ahigh-voltage power feeding bracket removably provided at the electricalbox. The high-voltage power feeding bracket has a high-voltage powerfeeding terminal at one end thereof, and has a high-voltage powerconnector at other end thereof. The high-voltage power connectorcontacts the high-voltage power supply board with a pressure as to fixthe high-voltage power supply board to the electrical box.

This structure allows the high-voltage power feeding bracket to be fixedto the electrical box, while the high-voltage power connector of thehigh-voltage power feeding bracket contacts the high-voltage powersupply board. In this way, the high-voltage power supply board is easilyfixed in the electrical box.

According to another aspect of the invention, an electric dust collectoris arranged to be mounted in an air channel and to be connected to ahigh voltage power supply. The electric dust collector includes a limitswitch having an operation lever for turning on and off the high voltagepower supply, a holding unit mounted at the air channel and holding thelimit switch, a dust-collecting unit removably attached to the holdingunit, a folded elastic member provided at the holding unit, the foldedelastic member facing the operation lever of the limit switch, and aswitch operation rib provided at the dust-collecting unit. The switchoperation rib activates the folded elastic member. When thedust-collecting unit is attached to the holding unit, a force is appliedthrough the switch operation rib to the folded elastic member as toallow the folded elastic member to deform. The folded elastic member,upon deforming, produces a repulsion force for moving the operationlever to activate the limit switch.

In the electric dust collector having the above structure, the repulsionforce produced generated from the deformation of the elastic member canaccommodate variations in positioning the limit switch, providingaccurate operation of the limit switch.

According to another aspect of the invention, the folded elastic memberhas a U-shape or V-shape.

If an excessive force from the switch operation rib is applied to theelastic member, the U-shaped or V-shaped bend can absorb the force andproperly control the switch operation of the limit switch.

According to another aspect of the invention, the electric dustcollector may further include a support rib integrally formed with theholding unit for movably supporting the folded elastic member.

This structure allows the elastic member to be easily attached to theholding unit by fitting a folded portion into the support rib. Besides,the support rib allows an operation force to be reliably transmitted.

According to still another aspect of the invention, the holding unit mayhave an opening formed therein for allowing the switch operation rib isinserted through the opening when the switch operation rib moves. Arib-side arm of the folded elastic member facing the switch operationrib is larger than the opening of the holding unit. The rib-side arm ofthe folded elastic member almost covers the opening when the switchoperation rib moves away from the opening.

When the dust-collecting unit is removed, the rib-side arm of the foldedelastic member covers the opening from inside, preventing dust fromentering to the limit switch through the opening. The structure canprotect the limit switch from collecting dust that may cause switchingfailure.

According to another aspect of the invention, a lever-side arm of thefolded elastic member facing the operation lever of the limit switch mayhave a size approximately identical to a size of the limit switch.

This lever-side arm of the folded elastic member can prevent dust fromentering toward the limit switch even if dust enters inside the rib-sidearm of the folded elastic member.

According to another aspect of the invention, the folded elastic membermay be formed integrally on an end of the operation lever.

The structure can form the limit switch and the folded elastic memberinto one-piece, thereby simplifying assembly work and management ofparts inventories.

According to still another aspect of the invention, the folded elasticmember may include a coil spring. An elastic force of the coil springactivates the operation lever of the limit switch.

In this structure, the elasticity of the coil spring can absorb anexcessive force from the switch operation rib, controlling the operationof the limit switch properly, and further, contributing to aspace-saving installation.

According to still another aspect of the invention, an electric dustcollector is arranged to be mounted in an air channel and to beconnected to a high-voltage power supply. The electric dust collectorincludes a switching unit for turning on and off the high-voltage powersupply, a holding unit having a shape to be placed in the air channeland for holding the switching unit, a dust collecting unit removablyprovided on the holding unit and having both sides substantiallysymmetric to each other, a ground connecting terminal provided on theholding unit, a ground terminal provided on one of the both sides of thedust collecting unit and electrically connected with the groundconnecting terminal, and a high-voltage power receiving terminalprovided on the one of the both sides of the dust collecting unit. Thehigh-voltage power receiving terminal is arranged to be electricallyconnected with the high-voltage power supply.

With the structure above, a component is changed in its location betweenthe left and the right sides to be applicable for the dust-collectingunit to be attached to the holding unit no matter whether thehigh-voltage power supply is located on left or right of the holdingunit. The dust-collecting unit can thus used for the right and left.

According to another aspect of the invention, the electric dustcollector may further include a switch operation rib provided on thedust collecting unit to activate the switching unit, a firstdrop-protection supporter for holding the dust collecting unit, and asecond drop-guard supporter provided on the surface of the holding uniton which the dust-collecting unit is mounted. The first drop-guardsupporter is provided on a surface of the holding unit. This surface ofthe dust-collecting unit has the dust collection unit mounted thereon.The second drop-protection supporter is closer to the switching unitthan the first drop-guard supporter. The second drop-protectionsupporter has a holding power is smaller than a holding power of thefirst drop-guard supporter.

This structure allows the dust-collecting unit to be easily pulled outwithout torsion.

According to another aspect of the invention, the first drop-guardsupporter may include a first head having a spherical shape, and a firstcoil spring for pushing the first head. The second drop-guard supportermay include a second head having a spherical shape, and a second coilspring for pushing the second head. The second coil spring is differentfrom the first coil spring in at least one of shape and material.

With the structure above, different bearing power can be given to eachcoil spring of the drop-guard supporters by providing a minor change inshape or material of the coil spring.

According to another aspect of the invention, the first drop-protectionsupporter may include a first head having a spherical shape, a firstcoil spring for pushing the first head, and a first housing foraccommodating the first coil spring. The second drop-guard supporter mayinclude a second head having a spherical shape, a second coil spring forpushing the second head, and a second housing for accommodating thesecond coil spring. The second housing has an accommodating sizedifferent from an accommodating size of the first housing.

The structure above eliminates the need for preparing different types ofthe coil spring, contributing to standardization of components to beused.

According to another aspect of the invention, the electric dustcollector may further include a high-voltage power supply unit having ashape mountable to the holding unit and having both sides substantiallysymmetrical to each other, and a first high-voltage power feedingterminal and a first ground connecting terminal mounted to one of theboth sides of the high-voltage power supply unit. The high-voltage powersupply unit functions as the high-voltage power supply. The firsthigh-voltage power feeding terminal and the first ground connectingterminal are capable of each of the both sides of the high-voltage powersupply unit. The high-voltage power receiving terminal and the groundterminal are provided at the dust-collecting unit so as to correspond tothe first high-voltage power feeding terminal and the first groundconnecting terminal, respectively.

With the structure above, the high-voltage power supply unit can be usedcommonly.

As another aspect of the present invention, the electric dust collectormay further include a second high-voltage power feeding terminal and asecond ground connecting terminal that are provided at other of the bothsides of the high-voltage power supply unit, another holding unitprovided on the other of the both sides of the high-voltage power supplyunit, and another dust-collecting unit attached to the another holdingunit.

This structure allows components for home use to expand to large-sizedstructure for business or industry use.

According to another aspect of the invention, the electric dustcollector may further include a pair of rails provided on upper sides ofthe dust-collecting unit, and a pair of eaves provided on the holdingunit so as to slidably hold the rails. The rails are parallel with eachother.

With the structure above, the dust-collecting unit can be attached orremoved without torsion no matter whether the switching unit is providedon the right or the left.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a high-voltage applying device of anelectric dust collector of Exemplary Embodiment 1 of the presentinvention.

FIG. 1B is a front view of a filter unit of the electric dust collectorof Embodiment 1.

FIG. 1C is a section view of an essential part of the electric dustcollector of Embodiment 1.

FIG. 2 is a front view of a holding unit of the electric dust collectorof Embodiment 1.

FIG. 3 is a side view of the electric dust collector for showing a guiderib of Embodiment 1.

FIG. 4 is a section view of the electric dust collector for showing anengaging unit of Embodiment 1.

FIG. 5 is a front view of the filter unit of the electric dust collectorof Embodiment 1.

FIG. 6 is a front view of a filter unit of an electric dust collector ofExemplary Embodiment 2 of the invention.

FIG. 7 is a section view of a filter unit of an electric dust collectorof Exemplary Embodiment 3 of the invention.

FIG. 8 is a front view of a holding unit of the electric dust collectorof Embodiment 3.

FIG. 9 is a front view of the filter unit of the electric dust collectorof Embodiment 3.

FIG. 10 is a perspective view of the electric dust collector for showingan engaging section for engagement with a conductive rib of Embodiment3.

FIG. 11 is a perspective view of an essential part of the electric dustcollector of Embodiment 3.

FIG. 12 is a perspective view of a ground electrode of the electric dustcollector of Embodiment 3.

FIG. 13 is a perspective view of the electric dust collector ofEmbodiment 3.

FIG. 14 is a front view of an essential part of the electric dustcollector of Embodiment 3.

FIG. 15 is a front view of an essential part of a sub-electrode plate ofthe electric dust collector of Embodiment 3.

FIG. 16 is a section view of the electric dust collector of Embodiment3.

FIG. 17 is a front view of the electric dust collector for showing afilter frame of Embodiment 3.

FIG. 18 is a side view of the electric dust collector of the Embodiment3.

FIG. 19 is an exploded perspective view of the electric dust collectorof Embodiment 3.

FIG. 20 is an exploded perspective view of the electric dust collectorof Embodiment 3.

FIG. 21 is an enlarged view of the electric dust collector of Embodiment3.

FIG. 22 is an exploded perspective view of an electric dust collector ofExemplary Embodiment 4 of the invention.

FIG. 23 is a plan view of the electric dust collector of Embodiment 4.

FIG. 24 is a plan view of the electric dust collector of Embodiment 4.

FIG. 25 is a section view of the electric dust collector of Embodiment4.

FIG. 26 is a perspective view of the electric dust collector ofEmbodiment 4.

FIG. 27 is a partial view of an electric dust collector of ExemplaryEmbodiment 5 of the invention.

FIG. 28A is a partial view of the electric dust collector of Embodiment5.

FIG. 28B is a section view of the electric dust collector taken alongline 28B-28B shown in FIG. 28A.

FIG. 29A is a front view of the electric dust collector and a holdingunit of Embodiment 5.

FIG. 29B is a front view of the electric dust collector and the holdingunit of Embodiment 5.

FIG. 30 is a front view of the electric dust collector of Embodiment 5.

FIG. 31 is a partial view of another electric dust collector ofEmbodiment 5.

FIG. 32A is a partial view of an electric dust collector of ExemplaryEmbodiment 6 of the invention.

FIG. 32B is a partial view of the electric dust collector of Embodiment6.

FIG. 33 is a partial view of the electric dust collector of Embodiment6.

FIG. 34 is a partial view of an electric dust collector of ExemplaryEmbodiment 7 of the invention.

FIG. 35 is a front view of an electric dust collector of ExemplaryEmbodiment 8 of the invention.

FIG. 36 is a partial view of the electric dust collector of Embodiment8.

FIG. 37 is a partial view of an electric dust collector of ExemplaryEmbodiment 9 of the invention.

FIG. 38 is a front view of a dust-collecting unit of an electric dustcollector of Exemplary Embodiment 10 of the invention.

FIG. 39 is a partial view of the electric dust collector and the holdingunit of Embodiment 10.

FIG. 40 is a front view of the electric dust collector of ExemplaryEmbodiment 10.

FIG. 41 is a partial view of the electric dust collector and the holdingunit of Embodiment 10.

FIG. 42 is a front view of a holding unit of an electric dust collectorof Exemplary Embodiment 11 of the invention.

FIG. 43 is a front view of a dust-collecting unit of the electric dustcollector of Embodiment 11.

FIG. 44 is an enlarged view of the electric dust collector shown in FIG.42.

FIG. 45 is an enlarged view of the electric dust collector shown in FIG.42.

FIG. 46 is a partial view of an electric dust collector of ExemplaryEmbodiment 12 of the invention.

FIG. 47 is a partial view of the electric dust collector of Embodiment12.

FIG. 48 is a front view of a high-voltage power supply unit of anelectric dust collector of Exemplary Embodiment 13 of the invention.

FIG. 49 is a partial view of the electric dust collector of Embodiment13.

FIG. 50 is a partial view of the electric dust collector of Embodiment13.

FIG. 51A is an exploded front view of an electric dust collector ofExemplary Embodiment 14 of the invention.

FIG. 51B is an exploded front view of the electric dust collector of theEmbodiment 14.

FIG. 51C is an exploded front view of the electric dust collector ofEmbodiment 14.

FIG. 52A is a front view of an electric dust collector of ExemplaryEmbodiment 15 of the invention.

FIG. 52B is a section view of the electric dust collector at along line52B-52B shown in FIG. 52A.

FIG. 52C is a section view of the electric dust collector at line52C-52C shown in FIG. 52A.

FIG. 53 is a front view of a conventional electric air purifier.

FIG. 54 is a side view of the conventional electric air purifier.

FIG. 55 is a perspective view of a filter body of the conventionalelectric air purifier.

FIG. 56 is a section view of a filter unit of a conventional electricdust-collecting unit for showing its structure.

FIG. 57 is a rear view of a filter frame of the conventional electricdust-collecting unit.

FIG. 58 is a front view of the filter unit of the conventional electricdust-collecting unit.

FIG. 59 is an exploded perspective view of another conventional electricdust collector.

FIG. 60 is a section view of a conventional air purifier.

FIG. 61 is a perspective view of a pre-filter of the conventional airpurifier.

FIG. 62 is a front view of another conventional electric dust collectingunit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Exemplary Embodiment 1

FIG. 1A is a perspective view of a high-voltage applying device of anelectric dust collector according to Exemplary Embodiment 1 of thepresent invention. FIG. 1B is a front view of a filter unit of theelectric dust collector of Embodiment 1. FIG. 1C is a section view of anessential part of the electric dust collector of Embodiment 1. FIG. 2 isa front view of a holding unit of the electric dust collector ofEmbodiment 1. FIG. 3 is a side view showing a guide rib of the electricdust collector of Embodiment 1. FIG. 4 is a section view of an engagingunit of the electric dust collector of Embodiment 1. FIG. 5 is a frontview of the filter unit of the electric dust collector of Embodiment 1.

As shown in FIG. 1A to FIG. 5, high-voltage applying device 2 providedat an end of oblong holding unit 1 provided in an air channel of an airconditioner (not shown). Flat spring-shaped high-voltage power feedingterminal 3 connected to high-voltage applying device 2 is provided incontact protector 5 with front opening 4 of substantially invertedU-shape for accommodating high-voltage power feeding terminal 3. Slideprojection 7 removably provided on filter unit 8 has high-voltage powerreceiving terminal 6 removably fitted into contact protector 5, allowingfilter unit 8 to be removably attached to holding unit 1. Filter unit 8has air-intake grill 10 having discharge needle 9 connected tohigh-voltage power receiving terminal 6. Ground electrode 11 and dustcollecting filter 12 are provided on leeward side of discharge needle 9.Air-intake grill 10 has handle 13 with which filter unit 8 is fixed toor removed from holding unit 1.

Guide rib 14 is provided at high-voltage applying device 2 so as to beparallel to the direction in which filter unit 8 is pulled out. Foraccepting guide rib 14, filter unit 8 has groove 15 that reachessubstantially the midpoint of filter unit 8. Filter unit 8 contains dent16 and engaging projection 17. Dent 16 is provided at an end of filterunit 8 opposite to the end having high-voltage power receiving terminal6. Engaging projection 17, which is elastically engaged with dent 16, isprovided on a side opposite to the side having high-voltage applyingdevice 2 of holding unit 1. Dent 16 and projection 17 provide latchingunit 18 so as to temporarily fix filter unit 8 to holding unit 1 whenfilter unit 8 is pulled out.

In the above structure, when air flows into filter unit 8 that isprovided via holding unit 1 on the air channel of the air conditioner,ground electrode 11 and negative high-voltage applied via high-voltagepower receiving terminal 6 to discharge needle 9 provided on air-intakegrill 10 generate a large electric field around discharge needle 9. Inan area affected by the electric field, separation and union ofelectrons of air molecules, ionized air molecules provide air ions. Theforce of the electric field causes the air ions to spread around andstick to dust, and causes dust particles bear to be electricallycharged. The charged dust particles avoid interference between particlesand gather to dust collecting filter 12 provided on the leeward side ofground electrode 11, thus allowing the dusts to be collected.

To remove the dust accumulated on the filter unit, filter unit 8 ispulled out from holding unit 1 with handle 13. In the structure, filterunit 8 is fixed to holding unit 1. At one side of filter unit 8, slideprojection 7 having high-voltage power receiving terminal 6 provided onfilter unit 8 is removably fitted in contact protector 5 with frontopening 4 having a recess shape and accommodates elastic high-voltagepower feeding terminal 3 connected to high-voltage applying device 2. Atthe other side of filter unit 8, dent 16 provided on filter unit 8 hasan elastic engagement with engaging projection 17 provided on holdingunit 1, which forms latching unit 18 for temporarily retaining filterunit 8. Therefore, filter unit 8 can be retained with almost the sameconnecting power given on its both sides. Filter unit 8 can be pulledout with handle 13 in a manner that guide rib 14 on holding unit 1slides along groove 15 on filter unit 8. After removed from holding unit1, filter unit 8 is washed by water to remove dust. When dust collectingfilter 12 is replaced, filter unit 8 is removed.

After cleaning filter unit 8 or replacing dust-collecting unit 12,filter unit 8 is mounted on holding unit 1. Slide projection 7 havingreceiving terminal 6, which is provided on one side of filer unit 8, isengaged with front opening 4 of contact protector 5. Then, filter unit 8is moved toward the fixing position on the side of holding unit 1. Oneside of filter unit 8 is guided by engagement of groove 15 provided onfilter unit 8 and guide rib 14 provided on holding unit 1. High-voltagepower receiving terminal 6 of slide projection 7 is elastically engagedwith high-voltage power feeding terminal 3 in contact protector 5. Atthe other side of filter unit 8, engaging projection 17 on holding unit1 which forms latching unit 18 is engaged elastically with dent 16 onfilter unit 8, thus having filter unit 8 mounted on holding unit 1.

According to Embodiment 1, as described above, the electric dustcollector includes oblong holding unit 1 provided in an air channel ofan air conditioner and the like, high-voltage applying device 2 providedat an end of holding unit 1, contact protector 5 having front opening 4of substantially inverted U-shape for accommodating flat spring-shapedhigh-voltage power feeding terminal 3 connected to high-voltage applyingdevice 2, filter unit 8 removably attached to holding unit 1, and slideprojection 7 removably provided on filter unit 8. Slide projection 7 hashigh-voltage power receiving terminal 6 removably fitted into contactprotector 5, allowing filter unit 8 to be removably attached to holdingunit 1. The structure in which high-voltage power feeding terminal 3 iscovered with contact protector 5 having inverted U-shape can keephigh-voltage power feeding terminal 3 from collecting dust. Thestructure not only prevents contact failure or electrical leak that ispossibly caused by dust, but also protects hands or fingers fromaccidentally touching high-voltage power feeding terminal 3, therebyincreasing safety. Besides, compared to the structure in whichapplication of high voltage is controlled by a limit switch, theelectric dust collector of the present invention can provide acost-reduced simple structure.

Besides, in the structure above, guide rib 14 is provided on holdingunit 1 or high-voltage applying device 2 so as to be parallel to thedirection in which filter unit 8 is pulled out, and on filter unit 8,groove 15, through which guide rib 14 slides, reaches substantially themidpoint of filter unit 8. This structure allows filter unit 8 to bemoved in substantially parallel direction between one end of holdingunit 1 and high-voltage applying device 2, with guide rib 14 met withgroove 15. In this way, filter unit 8 can be smoothly removed withouttorsion, eliminating problems caused by torsion.

In addition, latching unit 18, by which filter unit 8 is temporarilyretained by holding unit 1, is provided on a side of filter unit 8opposite to the side having high-voltage power receiving terminal 6.Having latching unit 18 increases connecting force on the side oppositeto the side having the high-voltage applying device as substantially thesame as the side having high-voltage power feeding terminal 3. Thestructure allows the side opposite to the side having the high-voltageapplying device to pull off first, thereby eliminating difficulties withtorsion in removing filter unit 8.

Although guide rib 14 is provided on high-voltage applying device 2 inthe first exemplary embodiment, it is not limited thereto. Forming guiderib 14 on holding unit 1 can offer similar effect.

Exemplary Embodiment 2

FIG. 6 is a front view of a filter unit of an electric dust collectoraccording to Exemplary Embodiment 2 of the present invention. In thestructure, handle 13A is positioned on filter unit 8A so as to beshifted toward the side of high-voltage power receiving terminal 6A.

In the structure above, high-voltage power receiving terminal 6Aprovided on slide projection 7A has electrical connections with thehigh-voltage power feeding terminal in the contact protector provided onthe high-voltage applying device of the holding unit (not shown). Theelectrical connections allow the side of high-voltage power receivingterminal 6A to provide a connecting force tighter than the other side offilter unit 8A. When filter unit 8A is pulled out by using handle 13Aprovided at the midpoint of filter unit 8A, the side with looserconnecting force, i.e., the side opposite to the side havinghigh-voltage applying device, tends to come off ahead, thereby causingtorsion. However, by disposing handle 13A on filter unit 8A so as toshift toward the side with tighter connecting force, i.e., the side ofhigh-voltage power receiving terminal 6A, pulling-out force with handle13A is strongly applied to the side of high-voltage power receivingterminal 6A, whereby both sides can be pulled out substantiallysimultaneously without torsion.

In the electric dust collector according to Embodiment 2, handle 13A isprovided to shift toward the side of high-voltage power receivingterminal 6A, on filter unit 8A. Pulling-out force with handle 13A isstrongly applied to the side that attaches to the holding unit tighterthan the opposite side having high-voltage power receiving terminal 6A,whereby the tighter-connected side can be pulled out at almost the sametime with the other side, encouraging a smooth pull-out of filter unit8A.

Exemplary Embodiment 3

FIG. 7 is a section view of a filter unit of an electric dust collectoraccording to Exemplary Embodiment 3 of the present invention. FIG. 8 isa front view of a holding unit of the electric dust collector ofEmbodiment 3. FIG. 9 is a front view of a filter unit of the electricdust collector of Embodiment 3. FIG. 10 is a perspective view of anengaging section having an engagement with a conductive rib of theelectric dust collector of Embodiment 3. FIG. 11 is a perspective viewof the essential part of the electric dust collector of Embodiment 3.FIG. 12 is a perspective view of a ground electrode of the electric dustcollector of Embodiment 3. FIG. 13 is a perspective view of the electricdust collector of Embodiment 3. FIG. 14 is a front view of the essentialpart of the electric dust collector of Embodiment 3. FIG. 15 is a frontview showing the essential part of a sub-electrode plate of the electricdust collector of Embodiment 3. FIG. 16 is a section view of theelectric dust collector of Embodiment 3. FIG. 17 is a front view showinga filter frame of the electric dust collector of Embodiment 3. FIG. 18is a side view of the electric dust collector of Embodiment 3. FIG. 19is an exploded perspective view of the electric dust collector ofEmbodiment 3. FIG. 20 is an exploded perspective view of the electricdust collector of Embodiment 3. FIG. 21 is an enlarged view of theelectric dust collector of Embodiment 3.

As shown in FIG. 7 to FIG. 21, high-voltage applying device 1002 isprovided on one end of oblong holding unit 1001 located at an airchannel in an air conditioner (not shown) or the like. Filter unit 1007is removably mounted on holding unit 1001. Filter unit 1007 includesdischarge needle 1003 having electrical connections to high-voltageapplying device 1002, front-swelled air-intake grill 1004, and groundelectrode 1005 and dust collecting filter 1006 provided on the leewardside of discharge needle 1003.

Air-intake grill 1004 includes non-conductive rib 1008 made ofnon-conductive resin, and lattice-shaped conductive rib 1009 made ofconductive resin. The tip of discharge needle 1003 is surrounded byconductive rib 1009 on a projection plane. Air-intake grill 1004contains handle 1010.

Pawl 1011 is formed on the tip of conductive rib 1009. Engaging section1012 of a caving shape is provided on air-intake grill 1004 made ofnon-conductive resin. Engaging pawl 1011 with engaging section 1012fixes conductive rib 1009 to air-intake grill 1004.

Ground electrode 15 has metallic frame 1013 on its perimeter, andair-permeable lath net 1005 a inside the frame. Frame 1013 made ofincludes plural holders 1014 b each of which has notch 1014 a that iscut out in a ladle-like shape—round hole led by a notch. Ladle-likeprojection 1009 a is formed on conductive rib 1009. Projection 1009 a isfitted into notch 1014 a of holders 1014 b of ground electrode 1005,forming connecting unit 1014 between conductive rib 1009 and groundelectrode 1005. Conductive rib 1009 is connected to ground electrode1005 in such a way that connecting unit 1014 sandwiches non-conductiverib 1008 of air-intake grill 1004.

The shortest distance “La” (in FIG. 7) between the tip of dischargeneedle 1003 and ground electrode 1005 is determined to be substantiallyidentical to the shortest distance “Lb” (in FIG. 14) between the tip ofdischarge needle 1003 and conductive rib 1009 of air-intake grill 1004.Round and flat sub-electrode plate 1015 is provided at a positionnearest from ground electrode 1005.

The electric dust collector includes dust-collecting filter 1006 that isaccommodated in frame 1013 of ground electrode 1005, burrs 1016 formedon the outer side of the frame in a cutting procedure, and filter unitframe 1018 surrounding the filter unit through clearance 1017 of frame1013 of ground electrode 1005. In the structure, the frame wall heightof filter unit frame 1018, which is measured from ground electrode 1005as a reference plane, is determined to be higher than the height offrame 1013 having burrs 1016 of ground electrode 1005. The thickness ofdust-collecting filter 1006 is determined to be greater than the framewall height of frame 1013 of ground electrode 1005.

Lattice-shaped inflexible filter frame 1019 is movably provided onair-intake grill 1004. Filter frame 1019 holds the side of the openingof dust-collecting filter 1006 that is accommodated in ground electrode1005. Small projection 1020 is provided on lattice 1019 a of filterframe 1019 so as to face dust-collecting filter 1006.

In an electric dust collector of Embodiment 3 of the invention,accommodating groove 1021 having an oblong shape and electrode unit 1022having a needle shape are provided on the front side of air-intake grill1004. Needle-shaped electrode unit 1022 is formed of connected dischargeneedles 1003 and is accommodated in groove 1021. The dust collectorfurther includes bend 1024 having an L-shape serving as a high-voltagepower receiving terminal of needle-shaped electrode unit 1022 and fittedin slide projection 1023 provided on the edge of filter unit 1007,needle-electrode cover 1025 for covering needle-shaped electrode unit1022 fitted in groove 1021, and pressing rib 1026 provided onneedle-electrode cover 1025. Needle-shaped electrode unit 1022 has dentportion 1027. Pressing rib 1026 contacts dent portion 1027 ofneedle-shaped electrode unit 1022, so that needle-shaped electrode unit1022 is secured.

In the structure above, when the air flows into filter unit 1007provided via the holding unit on the air channel of an air conditioner,ground electrode 1005 and negative high-voltage that is applied viahigh-voltage power receiving terminal 6 to discharge needle 9 providedon air-intake grill 1004 generates a great electric field arounddischarge needle 1003. In an area affected by the electric field, byseparation and bonding of electrons of air molecules, ionized airmolecules become air ions. Under the force of the electric field, theair ions spread around and stick to dust, by which dust particles bearelectrical charges. The charged dust particles avoid interferencebetween particles and gather to dust collecting filter 1006, which isprovided on the leeward side of ground electrode 1005. Dust is thuscollected.

According the electric dust collector of Embodiment 3 of the invention,high-voltage applying device 1002 is provided on one end of oblongholding unit 1001 provided on the air channel of an air conditioner andthe like, and filter unit 1007 is removably provided on holding unit1001. Filter unit 1007 has discharge needle 1003 electrically connectedto high-voltage applying device 1002, front-swelled air-intake grill1004, air-permeable ground electrode 1005, and dust-collecting filter1006 on the leeward side of discharge needle 1003. Filter unit 1007 isremovably amounted on holding unit 1001. Non-conductive rib 1008 made ofnon-conductive resin, and lattice-shaped conductive rib 1009 made ofconductive resin are provided on air-intake grill 1004. Connectingconductive rib 1009 to ground electrode 1005 can dissipate staticcharges as they develop on air-intake grill 1004, thereby preventingdust collection on air-intake grill 1004. This can provide not only ahard-to-collect-dust, i.e., easy-to-clean structure, but also avoidshock hazards.

Air-intake grill 1004 is formed so that the tip of discharge needle 1003is surrounded by conductive rib 1009 on a projection plane. With thestructure above, the corona discharge from discharge needle 1003 can beperformed not only at ground electrode 1005 but also at conductive rib1009 of air-intake grill 1004. The structure extensively increases thedischarge area of negative ion, enhancing negative ionization of dust.This improves filtering efficiency of the dust collector, at the sametime, prevents air-intake grill 1004 from collecting dust to an area.

In addition, the shortest distance “La” between the tip of dischargeneedle 1003 and ground electrode 1005 is determined to be substantiallyidentical to the shortest distance “Lb” between the tip of dischargeneedle 1003 and conductive rib 1009 of air-intake grill 1004. With thestructure above, each amount of discharge from discharge needle 1003 toground electrode 1005 and to conductive rib 1009 can be balanced,whereby stable filtering efficiency is obtained. This structure canprotect components provided on the side of the ground from unevenlycollected dirt due to imbalance of discharge and from deteriorationcaused by dirt.

The electric dust collector includes pawl 1011 provided at the tip ofconductive rib 1009 of air-intake grill 1004, and engaging section 1012with a U-shape provided on air-intake grill 1004. The engagement ofengaging section 1012 with pawl 1011 attaches conductive rib 1009 toair-intake grill 1004. The structure above prevents arc discharge atdischarge needle 1003 and the tip of conductive rib 1009, enhancingsafety. Besides, the structure provides reliable positioning ofconductive rib 1009, simplifying the assembly work.

The structure includes ground electrode 1005 having frame 1013 made ofmetal around the perimeter. Frame 1013 includes plural connecting unit1014 with which frame 1013 of ground electrode 1005 is attached toconductive rib 1009 of air-intake grill 1004. Connecting unit 1014sandwiches non-conductive rib 1008 of air-intake grill 1004. Thestructure can eliminate the need for using fixing parts, such as screws,thereby contributing to a simplified assembly work. Once assembled,ground electrode 1005 with a frame structure and air-intake grill 1004forms a rigidly united filter unit 1007, providing strength againstmounting on, or dismounting from holding unit 1001. This structure canprevent vibration noise caused by resonance in operation.

In the structure of the embodiment, sub-electrode plate 1015 having aplate shape is provided on ground electrode 1005 at a position havingthe shortest distance from discharge needle 1003. The structure abovecan protect lath net 1005 a forming ground electrode 1005 fromcollecting dust to the edge of lath net 1005 a due to partiallyperformed corona discharge, preventing deterioration caused by dustcollection. This structure can improve filtering efficiency byincreasing the area of corona discharge to ground electrode 1005.

The electric dust collector of the embodiment includes dust-collectingfilter 1006 that is accommodated in frame 1013 of ground electrode 1005,burrs formed on the outer side of frame 1013, and filter unit frame 1018surrounding the filter unit through clearance 1017 of frame 1013 ofground electrode 1005. In the structure, the frame wall height of filterunit frame 1018, which is measured from ground electrode 1005 as areference plane, is determined to be higher than the height of frame1013 of ground electrode 1005, and at the same time, the thickness ofdust-collecting filter 1006 is determined to be greater than the framewall height of frame 1013 of ground electrode 1005. That is, each of theframe wall of filter unit frame 1018 and the thickness ofdust-collecting filter 1006 is greater in height than burrs 1016 left onthe outer sides of frame 1013 of ground electrode 1005 when metalcutting procedures. The structure eliminates the need for removing burrs1016 by deflashing, thereby reducing manufacturing steps; accordingly,manufacturing cost.

An electric dust collector of the embodiment includes dust-collectingfilter 1006 having an opening. Dust-collecting filter 1006 is inflexibleand is accommodated in ground electrode 1005. Filter unit 1006 containslattice-shaped filter frame 1019 for holding the side of the opening ofdust-collecting filter 1006, and small projection 1020 provided onlattice 1019 a of filter frame 1019 so as to face dust-collecting filter1006. This structure provides a small space between dust-collectingfilter 1006 and filter frame 1019. The small space allows airflow to beevenly provided over the entire filter, improving filtering efficiency.

An electric dust collector of the embodiment includes accommodatinggroove 1021 having an oblong shape formed on the front side ofair-intake grill 1004, needle-shaped electrode unit 1022 connectingplural discharge needles 1003 having shapes accommodated in groove 1021,bend 1024 having an L-shape and serving as a high-voltage powerreceiving terminal of needle-shaped electrode unit 1022 and fitted inslide projection 1023 provided on the edge of filter unit 1007,needle-electrode cover 1025 for covering needle-shaped electrode unit1022 fitted in groove 1021, and pressing rib 1026 provided onneedle-electrode cover 1025. Needle-shaped electrode unit has dent 1027.Pressing rib 1026 contacts dent 1027 of needle-shaped electrode unit1022 to fix needle-electrode cover 1025. This structure allows dischargeneedles 1003 to be accurately fixed to a predetermined position onfilter unit 1007 through simple installation work without a screw or thelike. This can prevent poor filtering efficiency caused by inaccurateinstallation work.

According to Embodiment 3, the dust collector includes an oblong holdingunit provided in an air channel of an air conditioner and the like, ahigh-voltage applying device provided on one end of the holding unit,and a filter unit removably mounted on the holding unit. The filter unitincludes a front-swelled air-intake grill having a discharge needleelectrically connected to the high-voltage applying device, anair-permeable ground electrode and a dust-collecting filter on theleeward side of the discharge needle. The air-intake grill is formed ofa non-conductive rib made of non-conductive resin and a lattice-shapedconductive rib made of conductive resin. The conductive rib connected tothe ground electrode can prevent dust collection on the air-intakegrill. This can provide not only a hard-to-collect-dust, easy-to-cleanstructure, but also avoid shock hazards.

The air-intake grill is formed so that the tip of the discharge needleis surrounded by the conductive rib on a projection plane. The structureimproves filtering efficiency of the dust collector, at the same time,prevents concentrating dust to an area in the air-intake grill.

In addition, the shortest distance between the tip of the dischargeneedle and the ground electrode is determined to be substantiallyidentical to the shortest distance between the tip of the dischargeneedle and the conductive rib of the air-intake grill. The structure cannot only improve filtering efficiency, but also protect componentsprovided on the side of the ground from unevenly collected dirt due toimbalance of discharge and from deterioration caused by dirt.

The electric dust collector includes a pawl provided at the tip of theconductive rib of the non-conductive resin-made air-intake grill, and anengaging section with a caving shape provided on the air-intake grill.The engaging section engaged with the pawl attaches the conductive ribto the air-intake grill. The structure prevents arc discharge, enhancingsafety. Besides, the structure provides reliable positioning of theconductive rib, simplifying the assembling work.

The electric dust collector includes a ground electrode having a framemade of metal around the perimeter. The frame includes plural connectingunit, with which the frame of the ground electrode is attached to theconductive rib of the air-intake grill. The connecting unit sandwichesthe non-conductive rib of the air-intake grill. This structure allowsthe filter unit to have a rigid structure in a simplified assembly work.Besides, the structure can prevent vibration noise caused by resonancein operation.

In the structure of the embodiment, a sub-electrode plate having a plateshape is provided on the ground electrode at a position having theshortest distance from the discharge needle. The structure above canprotect a lath net forming the ground electrode from deteriorationcaused by unevenly collected dust. This structure can improve filteringefficiency.

The electric dust collector of the embodiment includes a dust-collectingfilter that is accommodated in the frame of the ground electrode, burrsformed on the outer side of the frame, and a filter unit framesurrounding the filter unit through a clearance of the frame of theground electrode. In the structure, the frame wall height of the filterunit frame (measured from the ground electrode as a reference plane) isdetermined to be higher than the height of the frame of the groundelectrode. The thickness of the dust-collecting filter is determined tobe greater than the frame wall height of the frame of the groundelectrode. The structure eliminates the need for removing the burrs bydeflashing, thereby not only removing worry about getting injury by theburrs, but also eliminating manufacturing processes, accordingly,reducing its manufacturing cost.

An electric dust collector of the embodiment includes a dust-collectingfilter with an opening. The dust-collecting filter is inflexible and isaccommodated in the ground electrode. The filter unit includes alattice-shaped filter frame for holding the side of the opening of thedust-collecting filter, and a small projection provided on the latticeof the filter frame so as to face the dust-collecting filter. Thestructure allows airflow to be evenly provided over the entire filter,improving filtering efficiency.

An electric dust collector of the embodiment includes an oblong grooveformed on the front side of the air-intake grill, a needle-shapedelectrode unit connecting plural discharge needles with shapesaccommodated in the groove, an L-shaped bend serving as a high-voltagepower receiving terminal of the needle-shaped electrode unit and fittedin a slide projection provided on the edge of the filter unit, aneedle-electrode cover for covering the needle-shaped electrode unitfitted in the groove, and a pressing rib provided on theneedle-electrode cover. The needle-shaped electrode unit has a dent. Thepressing rib contacts the dent of the needle-shaped electrode unit tofix the needle-electrode cover. This structure fixes the dischargeneedles accurately without a screw or the like to a predeterminedposition on the filter unit by simple installation work. This canprevent poor filtering efficiency caused by inaccurate installationwork.

Exemplary Embodiment 4

FIG. 22 is an exploded perspective view of an electric dust collector ofExemplary Embodiment 4 of the present invention. FIG. 23 is a plan viewof the electric dust collector of Embodiment 4. FIG. 24 is a plan viewof the electric dust collector of Embodiment 4. FIG. 25 is a sectionview of the electric dust collector of Embodiment 4. FIG. 26 is aperspective view of the electric dust collector of Embodiment 4.

As shown in FIG. 22 to FIG. 26, the electric dust collector has filterunit 2001 and holding unit 2002 on which filter unit 2001 is mounted,and includes electrical box 2003 provided on an end of holding unit2002, high-voltage power supply board 2004 and ultrasonic waveoscillator 2005 in electrical box 2003, opening 2006 in a side wall forpassing ultrasonic wave generated from ultrasonic wave oscillator 2005,Accommodating chamber 2008 having top-opening 2007, tubular projection2009 that surrounds ultrasonic wave oscillator 2005, and lid 2010 forchamber 2008. Having a diameter smaller toward opening 2007, tubularprojection 2009 is vertically divided in two; one is provided in chamber2008, and the other is provided inside lid 2010 that covers opening 2007of chamber 2008. Chamber 2008 is covered with lid 2010, providingtubular projection 2009 in chamber 2008.

The electric dust collector includes bracket holder 2012 having groove2011, and high-voltage power supply bracket. 2016. Bracket holder 2012with groove 2011 is provided on the top surface of lid 2010 of chamber2008 that accommodates ultrasonic wave oscillator 2005. High-voltagepower feeding terminal 2013 is provided on one end; and high-voltagepower connector 2014 is provided on the other end of high-voltage powersupply bracket 2016. High-voltage power feeding terminal 2013 has a bentstructure so as to provide an elastic force in a horizontal direction tofilter unit 2001 and so as to fit with groove 2011 of bracket holder2012. At the other end of bracket 2016, high-voltage power connector2014 is bent so as to contact power supply terminal 2004 a ofhigh-voltage power supply board 2004 with the elastic force. In themiddle of bracket 2016, rigid holding section 2015 is provided.Contacting lid 2010 of chamber 2008, high-voltage power feeding bracket2016 is fixed to electrical box 2003 with screw 2017. The end havinghigh-voltage power feeding terminal 2013 is retained by lid 2010 ofchamber 2008. High-voltage power connector 2014 is provided so as tohave an intimate contact with high-voltage power supply board 2004.

The electric dust collector includes lead-out wire 2018 extending fromhigh-voltage power supply board 2004 and connecting line 2020 connectedfrom outside electrical box 2003 to lead-out wire 2018 via connectingterminal 2019. Wires 2018 and 2020 are accommodated in small chamber2021 in electrical box 2003 so as to be fed with high-voltage powersupply. The opening of small chamber 2021 is closed with small-chamberlid 2022. Electrical box 2003 contains high-voltage power supply bracket2016 having high-voltage power feeding terminal 2013 and high-voltagepower connector 2014, high-voltage power supply board 2004, andelectrical-box lid 2023 that covers the top of electrical box 2003.

In the structure above, a high-voltage power supply which is transformedfrom commercial power supply at high-voltage power supply board 2004 issupplied from high-voltage terminal 2004 a to high-voltage powerconnector 2014 of high-voltage power supply bracket 2016, and further,is supplied to filter unit 2001 through high-voltage power feedingterminal 2013 provided on the other end of high-voltage power supplybracket 2016. At this moment, the high-voltage power supply is suppliedto the main unit (not shown) to drive a negative ions generator or thelike through lead-out wire 2018, connecting terminal 2019, andconnecting line 2020.

According to the structure of Embodiment 4, the electric dust collectorhas filter unit 2001 and holding unit 2002 on which filter unit 2001 ismounted, and includes electrical box 2003 provided on an end of holdingunit 2002, high-voltage power supply board 2004 and ultrasonic waveoscillator 2005 in electrical box 2003. Ultrasonic wave oscillator 2005is accommodated in top-open chamber 2008. Opening 2007 is closed withlid 2010. Disposing high-voltage power supply board 2004 and ultrasonicwave oscillator 2005 in electrical box 2003 can shorten the wiringlength, enhancing efficiency in workability and transportation. Besides,the structure not only contributes to a downsized electric dustcollector, but also protecting the ultrasonic wave oscillator an othercomponents from collecting dust that can cause deterioration ofultrasonic wave radiation.

The electric dust collector includes bracket holder 2012, andhigh-voltage power supply bracket 2016. Bracket holder 2012 is providedon the top surface of lid 2010 of chamber 2008 that accommodatesultrasonic wave oscillator 2005. High-voltage power feeding terminal2013 held by bracket holder 2012 is provided on one end of high-voltagepower supply bracket 2016. At the other end of bracket 2016,high-voltage power connector 2014 is provided. High-voltage powerconnector 2014 contacts power supply terminal 2004 a of high-voltagepower supply board 2004. High-voltage power supply bracket 2016 is fixedin electrical box 2003 so that the midsection of high-voltage powersupply bracket 2016 contacts lid 2010 of chamber 2008. High-voltagepower connector 2014 is provided so as to have an intimate contact withhigh-voltage power supply board 2004. High-voltage power supply bracket2016 is fixed adjacent to lid 2010 of chamber 2008 that accommodatesultrasonic wave oscillator 2005. Lid 2010 of chamber 2008 is securedthrough bracket holder 2012 on the side of high-voltage power feedingterminal 2013, and on the other side of high-voltage power supplybracket 2016, high-voltage power connector 2014 has an intimate contactwith high-voltage power supply board 2004. This structure can fix lid2010 and high-voltage power supply bracket 2016 simultaneously, therebyincreasing workability and decreasing parts count.

High-voltage power connector 2014 which has high-voltage power supplybrackets 2016 provided at its both ends and high-voltage power feedingterminal 2013 have elasticity. Holder section 2015 provided at themiddle to be fixed with screw 2017 has rigidity. High-voltage powersupply bracket 2016 is formed by bending a conductive metal plate, thusprovided by bending a single metal plate. This structure provideshigh-voltage power connector 2014 and high-voltage power feedingterminal 2013 with no use of plural materials, thereby reducing cost.This provides a structure having a small occupied area, secure fixing,and properly positioned contact points.

In order to feed ultrasonic wave generated from ultrasonic waveoscillator 2005 to filter unit 2001, opening 2006 is provided chamber2008. Tubular projection 2009 is formed of chamber 2008 and lid 2010 soas to surround ultrasonic wave oscillator 2005 and so as to face opening2006. Ultrasonic wave, which is radiated from ultrasonic wave oscillator2005, is led by tubular projection 2009 through opening 2006 of chamber2008 toward filter unit 2001 as a predetermined direction. Besides,tubular projection 2009 is divided in two sections; one is provided onthe side of chamber 2008, and the other one is provided on the side oflid 2010. Dividing tubular projection 2009 in two and disposing eachsection on the sides of chamber 2008 and lid 2010 allows ultrasonic waveoscillator 2005 to be vertically sandwiched between two sections. Thatis, the structure can not only securely retain ultrasonic waveoscillator 2005 even in small chamber 2008, but also simplifyinstallation work of ultrasonic wave oscillator 2005.

The electric dust collector includes lead-out wire 2018 extending fromhigh-voltage power supply board 2004 and connecting line 2020 connectedfrom outside electrical box 2003 to lead-out wire 2018 via connectingterminal 2019. Small chamber 2021 for surrounding connecting terminal2019 to prevent dust collection, and small-chamber lid 2022 are providedin electrical box 2003. That is, connecting terminal 2019 that connectsbetween lead-out wire 2018 and connecting line 2020 is located in smallchamber 2021 in electrical box 2003. The structure not only eliminatesthe need for additionally providing insulation for protecting connector2020, but also prevents dust collection, thereby enhancing safety.

High-voltage power supply bracket 2016 is secured to electrical box 2003with screws 2017, while high-voltage power connector 2004 ofhigh-voltage power supply bracket 2016 contacts high-voltage powersupply board 2004 with pressure, thereby fixing high-voltage powersupply board 2004 easily in electrical box 2003. According to Embodiment4, the electric dust collector includes an electrical box provided onone end of the holding unit on which the filter unit is mounted, and ahigh-voltage power supply board and an ultrasonic wave oscillator in theelectrical box. The ultrasonic wave oscillator is accommodated in atop-open chamber. The opening of the chamber is covered with a lid. Thestructure can shorten the lengths of wirings, thus contributing to adownsized electric dust collector. Besides, the structure protects theultrasonic wave oscillator from deterioration of ultrasonic waveradiation.

The electric dust collector includes a bracket holder and a high-voltagepower supply bracket. The bracket holder is provided on the top surfaceof a lid of a chamber that accommodates an ultrasonic wave oscillator. Ahigh-voltage power feeding terminal held by the bracket holder isprovided on one end of the high-voltage power supply bracket. At theother end of the high-voltage power supply bracket, a high-voltage powerconnector is provided. The high-voltage power supply bracket is fixed inthe electrical box so as to contact the lid of the chamber. Thehigh-voltage power connector has an intimate contact with thehigh-voltage power supply board. The structure above can fix the lid andthe high-voltage power supply bracket simultaneously, thereby increasingworkability and decreasing parts count.

The high-voltage power connector which has high-voltage the power supplybrackets provided at its both ends and the high-voltage power feedingterminal have elasticity. The holder section provided at the middle tobe fixed with the screw has rigidity. The high-voltage power supplybracket is formed by bending a conductive metal plate, thus provided bybending a single metal plate. This structure provides the high-voltagepower connector and the high-voltage power feeding terminal with no useof plural materials, thereby reducing cost. This provides a structurehaving a small occupied area, secure fixing, and properly positionedcontact points.

In an electric dust collector of the embodiment, the chamber has anopening for feeding ultrasonic wave from the ultrasonic wave oscillatorto the filter unit. In this case, a tubular projection is formed of thechamber and the lid so as to surround the ultrasonic wave oscillator andface to the opening.

With the structure above, the ultrasonic wave supplied from theultrasonic wave oscillator is not only guided in a predetermineddirection. Besides, the ultrasonic wave oscillator can be securelyretained even in the small chamber.

The electric dust collector includes a lead-out wire extending from thehigh-voltage power supply board, and a connecting line connected fromthe outside of the electrical box via a connecting terminal. Theelectrical box has a small chamber surrounding the connecting terminalto prevent dust collection. The structure above not only eliminates theneed for additionally providing insulation for protecting the connector,but also preventing dust collection, thereby enhancing safety.

The high-voltage power feeding bracket is fixed to the electrical box,while the high-voltage power connector of the high-voltage power feedingbracket contacts the high-voltage power supply board with pressure. Thehigh-voltage power supply bracket onto the electrical box, allowing thehigh-voltage power supply board to be easily fixed under pressure in theelectrical box.

Exemplary Embodiment 5

FIG. 27 is a partial view of an electric dust collector according toExemplary Embodiment 5 of the present invention. FIG. 28A is a partialview of the electric dust collector of Embodiment 5. FIG. 28B is asection view of the electric dust collector at line 28B-28B shown inFIG. 28A. FIG. 29A and FIG. 29B are front views of the electric dustcollector and a holding unit of Embodiment 5, respectively. FIG. 30 is afront view of the electric dust collector of Embodiment 5. FIG. 31 is apartial view of another electric dust collector of Embodiment 5.

As shown in FIG. 27 to FIG. 31, in the electric dust collector, holdingunit 3004 is provided in an air channel of an air conditioner and thelike. A dust-collecting unit is removably mounted on holding unit 3004.

The structure of the embodiment includes limit switch 3003 for turningon and off high-voltage power supply 3001, and folded elastic member3007 that is bent into U-shape and provided so as to face operationlever 3006 of limit switch 3003. Support rib 3009 engaged with bend 3008is provided on holding unit 3004. Folded elastic member 3007 having bend3008 is provided movable in support rib 3009 on holding unit 3004.Switch operation rib 3011 is provided on dust-collecting unit 3005. Whendust-collecting unit 3005 is attached to holding unit 3004, switchoperation rib 3011 protrudes from opening 3010 of holding unit 3004 tofolded elastic member 3007, and pushes rib-side arm 3012 of foldedelastic member 3007. As folded elastic member 3007 is tilted by thepushing force, lever-side arm 3013 of folded elastic member 3007 isaccordingly tilted in the direction of pushing operation lever 3006 oflimit switch 3003.

In the structure above, holding unit 3004 is provided in the air channelof the air conditioner and the like. With an upward movement,dust-collecting unit 3005 is fixed in the inside of holder 3014 providedon holding unit 3004. At this moment, the dust-collecting unit isattached to the holding unit, and switch operation rib 3011 ofdust-collecting unit 3005 comes into opening 3010 of holding unit 3004,pushing lever-side arm 3013 of folded elastic member 3007. Foldedelastic member 3007 movably provided to support rib 3009 tilts via bend3008. The tilting causes folded elastic member 3007 to contract inward,and generates repulsion in the outward direction of the arm. As aresult, lever-side arm 3013 of folded elastic member 3007 pushesoperation lever 3006 of limit switch 3003, and allows high-voltage powersupply from high-voltage power supply 3001 to be supplied todust-collecting unit 3005. Dust collection is thus carried out.

With the structure above, the repulsion generated from the elasticallyaltered elastic member 3007 can accommodate variations in positioningthe limit switch or switch operation rib 3011, providing accurateoperation of limit switch 3003.

Furthermore, folded elastic member 3007 having a U-shape can accommodatean excessive applying force from switch operation rib 3011, controllingproperly operation lever 3006 of limit switch 3003.

Bend 3008 is attached into support rib 3009 provided on holding unit3004, allows a pushing force to be reliably transmitted to the switchingoperation.

The same effect can be expected if folded elastic member 3007 ofEmbodiment 5 is formed to have a V-shape, as shown in FIG. 31.

Exemplary Embodiment 6

FIG. 32A is a partial view of an electric dust collector according toExemplary Embodiment 6 of the present invention. FIG. 32B is a partialview of the electric dust collector of Embodiment 6. FIG. 33 is apartial view of the electric dust collector of Embodiment 6.

As shown in FIG. 32A to FIG. 33, rib-side arm 3012A of folded elasticmember 3007A that faces switch operation rib 3011A is larger thanopening 3010A in which switch operation rib 3011A is inserted onmovement. In the structure above, when dust-collecting unit 3005A ismounted on holding unit 3004A, opening 3010A is covered with insertedswitch operation rib 3011A.

When dust-collecting unit 3005A is removed from holding unit 3004A,since rib-side arm 3012A is larger than opening 3010A, rib-side arm3012A of folded elastic member 3007A can cover opening 3010A, reducingdust entry on the side of limit switch 3003A. The structure can protectlimit switch 3003A from collecting dust that can invite switchingfailure.

Exemplary Embodiment 7

FIG. 34 is a partial view of an electric dust collector according toExemplary Embodiment 7 of the present invention. Lever-side arm 3013A offolded elastic member 3007B which faces operation lever 3006B of limitswitch 3003B is formed substantially in the same manner as limit switch3003B.

With the structure above, even if dust comes inside rib-side arm 3012Bof folded elastic member 3007B, lever-side arm 3013A, since being formedsubstantially the same as limit switch 3003B, can prevent the dust fromentering in the side of limit switch 3003B. The structure can protectlimit switch 3003B from collecting dust that can invite switchingfailure, providing the switching operation with accuracy.

Exemplary Embodiment 8

FIG. 35 is a front view of an electric dust collector according toExemplary Embodiment 8 of the present invention. FIG. 36 is a partialview of the electric dust collector of Embodiment 8.

As shown in FIG. 35 and FIG. 36, folded elastic member 3007C is fittedin the end of operation lever 3006C so as to work as an integralstructure.

In the structure above, when folded elastic member 3007C deforms with apushing force applied from the switch operation rib (not shown),repulsion is generated by the deforming of folded elastic member 3007C.The repulsion is smoothly applied to operation lever 3006C attached withfolded elastic member 3007C so as to turn on limit switch 3003C. Inaddition, limit switch 3003C and folded elastic member 3007C may beformed in one piece, simplifying assembling work and management of partsinventories.

Exemplary Embodiment 9

FIG. 37 is a partial view of an electric dust collector according toExemplary Embodiment 9 of the present invention. Holder 3015 is providedon limit switch 3003D having coil spring 3017 therein as an elasticmember is inserted. Pressed section 3016 pressed with the switchoperation rib (not shown) is provided at one end of coil spring 3017.

The other end of coil spring 3017 contacts operation lever 3006D oflimit switch 3003D so that an elastic force of coil spring 3017 isapplied to operation lever 3006D of limit switch 3003D.

In the structure above, when the switch operation rib pushes pressedsection 3016 provided at one end of coil spring 3017, the pressing forcecontracts coil spring 3017. The contraction produces repulsion thatmoves operation lever 3006D to turn on limit switch 3003D. The structurecan absorb variations in positional relationship between limit switch3003D and the switch operation rib, providing accurate operation oflimit switch 3003D. The a small component, i.e., coil spring 3017,provides space-saving installation.

Exemplary Embodiment 10

FIG. 38 is a front view of a dust-collecting unit of an electric dustcollector according to Exemplary Embodiment 10 of the present invention.FIG. 39 is a partial view of a holding unit of the electric dustcollector of Embodiment 10. FIG. 40 is a front view of the electric dustcollector of Embodiment 10. FIG. 41 is a partial view of the holdingunit of the electric dust collector of Embodiment 10.

As shown in FIG. 38 to FIG. 41, holding unit 4009 is provided in an airchannel of an air conditioner and the like, and dust-collecting unit4010 is removably mounted on holding unit 4009. The structure of theembodiment includes flat spring-like high-voltage power feeding terminal4001, ground connecting terminal 4004, limit switch 4006 for connectingand disconnecting the high-voltage power supply circuit, and switchingunit 4008 on the inner side of holding unit 4009. Ground connectingterminal 4004 has spherical head 4002 and coil spring 4003. Limit switch4006 which connects and disconnects the high-voltage power supplycircuit is controlled by switching unit 4008 formed of folded elasticmember 4007.

Dust-collecting unit 4010 has a substantially symmetric shape in whichits both sides have respective switch operation rib 4011 for activatingswitching unit 4008 of limit switch 4006. Ground terminal 4012,high-voltage power receiving terminal 4013, limit switch 4006, andfolded elastic member 4007 can be provided on either side of holdingunit 4009.

Dust-collecting unit 4010 includes needle-shaped electrode plate 4015having plural needle-shaped electrodes 4014. Needle-shaped electrodeplate 4015 is electrically connected to high-voltage power receivingterminal 4013. The structure of the embodiment further includes a filter(not shown) for collecting dust that is ionized by the application ofhigh voltage.

When high-voltage power feeding terminal 4001 and ground connectingterminal 4004 are located on the right of holding unit 4009, as shown inFIG. 39, dust-collecting unit 4010 is so structured that ground terminal4012 and high-voltage power receiving terminal 4013 are fixed on theright side of dust-collecting unit 4010, as shown in FIG. 38. Whendust-collecting unit 4010 is mounted on holding unit 4009, switchingunit 4008 activated with switch operation rib 4011 turns limit on switch4006, and simultaneously, high-voltage power feeding terminal 4001 andground connecting terminal 4004 provided on holding unit 4009 areelectrically connected to high-voltage power receiving terminal 4013 andground terminal 4012 provided on dust-collecting unit 4010,respectively, thus providing dust collecting operation.

When high-voltage power feeding terminal 4001 and ground connectingterminal 4004 are located on the left side of holding unit 4009, asshown in FIG. 41, dust-collecting unit 4010 is so structured that groundterminal 4012 and high-voltage power receiving terminal 4013 are fixedon the left side of dust-collecting unit 4010, as shown in FIG. 40. Inthis way, dust collecting is carried out in the same manner as theaforementioned structure having the high-voltage power feeding terminaland the ground connecting terminal on the right side.

That is, regardless of the locations that the high-voltage power supplywith high-voltage power feeding terminal 4001 and ground connectingterminal 4004 is provided on the right or the left of holding unit 4009,dust-collecting unit 4010 is adaptable for holding unit 4009 byreplacing the fixing position of high-voltage power receiving terminal4013 and ground terminal 4012 on dust-collecting unit 4010. Thestructure of the embodiment provides dust-collecting unit 4010 that canbe used commonly with differently structured holding units.

Exemplary Embodiment 11

FIG. 42 is a front view of a holding unit of an electric dust collectoraccording to Exemplary Embodiment 11 of the present invention. FIG. 43is a front view of a dust-collecting unit of the electric dust collectorof Embodiment 11. FIG. 44 is an enlarged view of the electric dustcollector shown in FIG. 42. FIG. 45 is an enlarged view of the electricdust collector shown in FIG. 42.

As shown in FIG. 42 to FIG. 45, switch operation rib 4011A foractivating switching unit 4008A of the high-voltage power supply circuitis provided on dust-collecting unit 4010A. A pair of drop-guardsupporters 4017 and 4017A for holding dust-collecting unit 4010A isprovided on the wall surface on which dust-collecting unit 4010A ismounted. Drop-guard supporter 4017A provided on one side functions as aground connecting terminal. Drop-protection supporter 4017 has sphericalhead 4002 and coil spring 4003 that pushes head 4002. Drop-guardsupporter 4017A has head 4002 and coil spring 4003A that pushes head4002. Coil springs 4003 and 4003A are accommodated in housing 4018.Drop-guard supporter 4017A is formed so as to have a bearing powerdifferent from the other drop-guard supporter by changing shape (e.g.diameter) or material—selecting a hard wire or a soft wire with a smallelasticity of coil spring 4003A. According to the embodiment, drop-guardsupporter 4017A is structured so as to have a bearing power smaller thanthe other drop-guard supporter.

When dust-collecting unit 4010A is removed from holding unit 4009A inthe aforementioned structure, the right side of dust-collecting unit4010A is subject to the engaging force of drop-guard supporter 4017added to the engaging force of switch operation rib 4010A and switchingunit 4008A, while the left side is subject to only the engaging force ofdrop-guard supporter 4017.

Drop-guard supporter 4017A has an engaging force smaller than that ofdrop-guard supporter 4017, thereby allowing dust-collecting unit 4010Ato be held by substantially even force on the right and left. Therefore,dust-collecting unit 4010A can be smoothly pulled out without leftwardtilting.

That is, dust-collecting unit 4010A has conventionally been keptunbalanced force between the right and the left since a contactresistance is greater on the side having switch operation rib 4011A foroperating switching unit 4008A provided on holding unit 4009A,high-voltage power receiving terminal 4013A, and ground terminal 4012Athan on the other side. Drop-guard supporter 4017A has a smaller bearingpower, allowing the dust-collecting unit to be held by substantiallyeven force on the right and left. With the structure, dust-collectingunit 4010A can be smoothly removed without torsion.

Drop-guard supporter 4017A has head 4002 and coil spring 4003A.Drop-guard supporter 4017A can have a bearing power smaller than that ofdrop-guard supporter 4017 by changing the number of turns, the diameter,or material of coil spring 4003A. That is, coil springs 4003 and 4003Amay be difference in shape or material, allowing dust-collecting unit4010A to be removed without torsion and simplifying the structure. Thedimension of housing 4018 can be commonly between the two coil springs.

Exemplary Embodiment 12

FIG. 46 is a partial view of an electric dust collector according toExemplary Embodiment 12 of the present invention. FIG. 47 is a partialview of the electric dust collector of Embodiment 12.

As shown in FIG. 46 and FIG. 47, drop-guard supporter 4017B is formed asone-piece structure in a manner that head 4002B is integrally formedwith an end of coil spring 4003B. Such structured drop-guard supporter4017B is accommodated in housings 4018A and 4018B that are provided onthe inner sides on the right and left of the holding unit (not shown).The structure of the embodiment employs housing 4018B having a sizedifferent from that of the other housing, by which different bearingpower can be obtained between the right and left sides.

As an example of changing the size of housing 4018B, the embodimentintroduces a structure having size-adjusting member 4019 on the bottomof housing 4018B. Member 4019 contracts coil spring 4003B by the lengthof member 4019, increasing the bearing power of head 4002B.

Drop-guard supporter 4017B is provided on the side opposite todrop-guard supporter 4017A, addressing the problem of unbalancedengaging force to the dust-collecting unit (not shown). Then, thedust-collecting unit can be smoothly pulled out without torsion. Coilspring 4003B can be employed for the structure above, contributing tostandardization of components.

Exemplary Embodiment 13

FIG. 48 is a front view of a high-voltage power supply unit of anelectric dust collector according to Exemplary Embodiment 13 of thepresent invention. FIG. 49 is a partial view of the electric dustcollector of Embodiment 13. FIG. 50 is a partial view of the electricdust collector of Embodiment 13.

As shown in FIG. 48 to FIG. 50, high-voltage power supply unit 4020 hashigh-voltage power supply 4005A having a shape mountable onto holdingunit 4009B and having both sides substantially symmetrical to each otherhigh-voltage power feeding terminal 4001A and ground connecting terminal4004C are provided on both side surfaces of high-voltage power supplyunit 4020 so that the dust-collecting unit can be attached to eitherside of high-voltage power supply unit 4020. The dust-collecting unitincludes high-voltage power receiving terminal 4013B and ground terminal4012B so as to correspond to high-voltage power feeding terminal 4001 Aand ground terminal 4004C.

When dust-collecting unit 4010B is provided on the left side ofhigh-voltage power supply unit 4020, limit switch 4006A for turning onand off high-voltage power supply 4005, switching unit 4008 for turningon and off limit switch 4006A, high-voltage power feeding terminal4001A, and ground connecting terminal 4004C are provided on the leftside of high-voltage power supply unit 4020. At the right side surfaceof dust-collecting unit 4010B, high-voltage power receiving terminal4013B and ground terminal 4012B are provided on positions correspondingto high-voltage power feeding terminal 4001A and ground connectingterminal 4004C. On the other hand, when dust-collecting unit 4010B isprovided on the right side of high-voltage power supply unit 4020, asindicated by the dash-double dot lines in the drawings, limit switch4006A, switching unit 4008B, high-voltage power feeding terminal 4001A,and ground connecting terminal 4004C are provided on the right side ofhigh-voltage power supply unit 4020. High-voltage power receivingterminal 4013B and ground terminal 4012B are provided on the left sideof dust-collecting unit 4010B. With the structure above, regardless ofthe locations that high-voltage power supply unit 4020 is positioned onthe right or the left of the holding unit, high-voltage power supplyunit 4020 can be used commonly with differently structureddust-collecting unit, with minor replacement of parts.

Exemplary Embodiment 14

FIG. 51A to FIG. 51C are exploded front views of an electric dustcollector according to Exemplary Embodiment 14 of the present invention.Having both side surfaces having shapes substantially asymmetrical toeach other, high-voltage power supply unit 4020A includes thehigh-voltage power supply (not shown), high-voltage power feedingterminal 4001B, and ground connecting terminal 4004D. Holding units4009C on which dust-collecting units 4010C are mounted are provided onboth side of high-voltage power supply unit 4020A.

In the structure above, each holding unit 4009C provided on both sidesof high-voltage power supply unit 4020A has respective dust-collectingunit 4010C. The structure above allows components for home use to beexpanded into the structure for business or industry use. Thiseliminates the need for producing another electric dust collector forbusiness or industry use, contributing to low-cost production andsimplified management of parts inventories.

Exemplary Embodiment 15

FIG. 52A is a front view of an electric dust collector according toExemplary Embodiment 15 of the present invention. FIG. 52B is a sectionview of the electric dust collector at line 52B-52B shown in FIG. 52A.FIG. 52C is a section view of the electric dust collector at line52C-52C shown in FIG. 52A.

As shown in FIG. 52A to FIG. 52C, a pair of rails are provided on bothupper sides of dust-collecting unit 4010D so as to be parallel with eachother Rails 4021 extend from each end to substantially the midpoint ofdust-collecting unit 4010D. Holding unit 4009D on which dust-collectingunit 4010D is removably mounted has a pair of eaves 4022 at a positioncorresponding to rails 4021. The end of eaves 4022 is vertically bent toform bend 4022A.

When dust-collecting unit 4010D is pulled out from holding unit 4009, anengaging force from switch operation rib (not shown) and the switchingunit (not shown) acts on the side having the switch operation rib, andtherefore the side comes off first. This has often invited torsion. Inthe structure of the embodiment, however, rails 4021 of dust-collectingunit 4010D is guided by eaves 4022 of holding unit 4009D and smoothlypulled out forward with sliding movement. Also in attaching operation,positioning rails 4021 to eaves 4022 and pushing allows dust-collectingunit 4010D to easily fix on holding unit 4009D with very littleresistance between the two units.

INDUSTRIAL APPLICABILITY

An electric dust collector according to the present invention canprevent a high-voltage power feeding terminal from dust collection. Thecollector prevents not only contact failure or electrical leak, but alsoprotects hands or fingers from accidentally touching the high-voltagepower feeding terminal, thereby increasing safety.

1. An electric dust collector comprising: an oblong holding unit mountedin an air channel of an air conditioner; a high-voltage applying deviceprovided at an end of the holding unit; and a filter unit removablyprovided on the holding unit, wherein the filter unit includes anair-intake grill having a shape having a center projecting to front, theair-intake grill having a first discharge needle electrically connectedto the high-voltage applying device, an air-permeable ground electrodeprovided on a leeward side of the first discharge needle, and anair-permeable dust-collecting filter provided on a leeward side of thefirst discharge needle, and wherein the air-intake grill includes anon-conductive rib made of non-conductive resin, and a conductive ribthat is provided in a lattice arrangement and is electrically connectedto the ground electrode.
 2. The electric dust collector of claim 1,wherein the first discharge needle has a tip surrounded by theconductive rib on a projection plane.
 3. The electric dust collector ofclaim 2, wherein a shortest distance between the tip of the firstdischarge needle and the ground electrode is substantially identical toa shortest distance between the tip of the first discharge needle andthe conductive rib of the air-intake grill.
 4. The electric dustcollector of claim 1, wherein a shortest distance between the tip of thefirst discharge needle and the ground electrode is substantiallyidentical to a shortest distance between the tip of the first dischargeneedle and the conductive rib of the air-intake grill.
 5. The electricdust collector of claim 1, further comprising: a pawl provided at an endof the conductive rib of the air-intake grill; and an engaging sectionprovided at the air-intake grill and having a caving shape, the engagingsection being engaged with the pawl to fix the conductive rib.
 6. Theelectric dust collector of claim 1, wherein the ground electrode has aframe made of metal at a perimeter thereof, said electric dust collectorfurther comprising a connecting unit for connecting the frame of theground electrode with the conductive rib of the air-intake grill at aplurality of positions, and wherein the connecting unit holds thenon-conductive rib of the air-intake grill.
 7. The electric dustcollector of claim 1, further comprising a flat sub-electrode plateprovided on the ground electrode at a shortest distance from the firstdischarge needle.
 8. The electric dust collector of claim 1, wherein theground electrode has a frame, said electric dust collector furthercomprising: a dust-collecting filter accommodated in the frame of theground electrode; a burr produced on an outer side of the frame; and afilter unit frame for surrounding the filter unit through a clearance ofthe frame of the ground electrode, wherein a frame wall-height of thefilter unit frame measured from the ground electrode as a referenceplane is larger than a frame-height of the ground electrode, and whereina thickness of the dust-collecting filter is larger than theframe-height of the ground electrode.
 9. The electric dust collector ofclaim 1, further comprising an inflexible dust-collecting filter havingan opening and accommodated in the ground electrode, wherein the filterunit includes a lattice-shaped filter frame for holding a side of theopening of the dust-collecting filter, and a small projection providedon the lattice of the filter frame and projecting toward thedust-collecting filter.
 10. The electric dust collector of claim 1,further comprising: a plurality of second discharge needles; aneedle-shaped electrode unit for connecting the second discharge needlesto each other, wherein the air-intake grill has a front side having anoblong groove formed therein, and the needle-shaped electrode unit has ashape accommodated in the oblong groove: a bend strip having an L-shapefitted in a slide projection provided on an edge of the filter unit, thebend strip serving as a high-voltage power receiving terminal of theneedle-shaped electrode unit; a needle-electrode cover for covering theneedle-shaped electrode unit fitted in the groove; and a pressing ribprovided at the needle-electrode cover, wherein, the needle-shapedelectrode unit has a dent portion formed therein, and wherein thepressing rib contacts the dent portion of the needle-shaped electrodeunit as to fix the needle-electrode cover.